Almost all passenger motor vehicles presently produced include some type of impact deployed restraint system to protect vehicle occupants, or others, during a vehicle impact event. Such restraint systems may include, for example, front and side airbags within the passenger compartment, side curtains, inflatable seat belts and seatbelt pretensioners. A restraint system may also include restraints for the protection of pedestrians involved in impacts with the vehicle, such as pedestrian airbags and hood release mechanisms. Sensing systems typically control the deployment of such restraints by detecting the occurrence of a vehicle impact event.
Sensing systems detect impact events through sensor elements, which are typically positioned at various areas prone to impact events throughout the vehicle. Sensor elements detect an impact event and, through various principles of operation, trigger deployment of one or several passive restraints in the vehicle as appropriate. Various types of sensors are utilized. For example, sensors comprised of piezoelectric cables, accelerometers, pressure sensors and crush-zone switches are frequently used. Also, deformation sensors can be used. These sensors generate an output, such as an electrical signal, that varies depending on the extent of deformation of the sensor. These sensors operate by physical participation in the impact event, i.e., they directly detect vehicle deformation. Therefore, these sensors can be utilized to detect an impact event and also to gather information regarding the rate and extent of deformation.
One type of deformation sensor is in the form of an elongated strip which may be oriented along a side door or bumper of a motor vehicle. Due to the configuration of some sensors, they are cumbersome, and their placement throughout the vehicle and installation can be a complex and time-consuming task. The modular assembly approach to vehicle manufacture increasingly demanded and practiced by automobile manufacturers has affected the design and componentry of motor vehicles in numerous ways. Several components are often joined together into an assembly or module, which is subsequently installed into the vehicle as a whole. This modular approach is designed to minimize the amount of assembly time during final production of a vehicle. Providing a modular approach to the installation of elongated impact deformation sensors could save time and make the task more manageable.
The design of an assembly for impact sensors must accommodate the functional qualities of the sensors, allowing the sensor to properly function even though contained within a housing. For example, deformation sensors must retain the ability to bend or deform once installed in the vehicle due to their mechanism of operation. For these deformation sensors, the ability of the sensor to bend or deform as the vehicle deforms is critical to the proper operation of the sensor. Therefore, any assembly or housing for these sensors must address this issue.
Also due to their mechanism of operation, deformation sensors may not detect an evenly applied impact that spans the length of the sensor. If such an impact occurs, it may force the entire sensor inward, not causing the bend or deformation of the sensor necessary to detect the impact. Conversely, deformation sensors may improperly generate a deployment signal due to minor deformations of the sensor element. For example, an unprotected sensor element may bend or deform in response to a rock or other object thrown at the vehicle. An ideal assembly for these sensors would therefore ensure proper deformation of the sensor during sensor-wide impacts while protecting the sensor from insignificant environmental impacts. Also, as with any vehicle component for installation during the manufacturing process and to be consistent with the goal of the modular approach to vehicle manufacturing, any impact sensor assembly should facilitate simple and efficient installation. The design of the assembly should be such that it is easily placed in its proper position and orientation. Furthermore, the assembly should allow for rapid connection to the necessary vehicle systems, such as a restraints control module.
Considering this background, there is a need for an assembly that provides a protective barrier for elongated impact sensor elements while ensuring proper operation during significant impact events. The assembly must allow proper functioning of the sensor and should facilitate the installation process, allowing for rapid and correct installation.